#include <iostream>
#include <string>
using namespace std;

int main()
{   string s;
    cout<<"vvedite posledovatelnost"<<endl;
    cin>>s;
    string s1;
    char a;
    for (int i=0;i<s.length();i++)
    {a=s[i];
      if ((a=='(') ||(a=='{') ||(a=='[') ||(a=='<') ||s1=="")
            s1+=a;
      else
      {
          if (s1!="")
          {
              if (((a==')')&&(s1[s1.length()-1]=='('))||((a==']')&&(s1[s1.length()-1]=='['))||((a=='>')&&(s1[s1.length()-1]=='<')))
                s1.pop_back();
          }
      }
    }
if (s1=="")
    cout<<"true";
else cout<<"false";
    return 0;
}
